Telephone system.



E. R. CORWIN. TELEPHONE SYSTEM. APPLIOATIOHr1LBD.rnB.2o,190B. RENEWED um 4,1911.

LMOSM. Patented on.8,1912.

IN i

ELMER R. CORWIN, OF CHICAGO. ILLINOIS. AES'IGNOH TCP CORTIN TITELEPHN'E 'MANU- FACTURING COMPANY, OF CHICAGO. '[lli'lil'NUlz, A CGR'PO'RA'JION OF ILL'NOIS.

TELEPHNE SYS'JEM.

Specification of Letters: tnteiit.

1,040,639. iitiint'til tlv t. tel, 'ttt tt L?.

i Application llled February 2G, 1908, Serial No, L1:16156. Renewed Muy ll, 1911 Serial No. 625.058.

To all 'whom 'it may confier/ri. loelted position when the suhserilier removesl Be it, known that I, ICL-MER R, nkwlx. his reeeiyer troiu the s\\'ilehhook while eona citizen of the United States ot America, IllittiUll 'IH milite with the line. 55 residing` at Chicago, in Cool; eount'ty, lllil prelierahly provide ezieh ott the pair oli 5 nois, have invented a new and useful Telo plugs in va pluga-ortl eouneetiugi eireuit with phone System, ot' which the, follmvino i5 n all ol' the relays ahore mentioned. to prospeeifieation, reference heilig had to tlie :if.-- Ville automatic ringing lor ein-h ot the plugs eonipanying drawing, illustrating same. aud to properly eouti-ol the operator`s eireuit 60 My invention relates to telephone systems :uid supervisory signals, :is will lie hereinand deals principally with the signaling' in ill'itli ilesorihetl, lau l wish it to lie imiter- Smgh Sysfmn. i stood that l may do away with the ringing The prineipal ohjeets olI my invention are relay and the lueliiugr relay assur-interi with to provide, nn improved automatie-iringiug one el' the plugs. it it is def-iireil to ring ont G5 arrangement 'for multiple telephone sysA over only one pluri; ot' the pair. t

l5 tenis; to provide improved means `lor eoul will now desi-i'ihe my iiiieution more in trolling the line signals in such systems; to detail, liy rel'ei'i-uee to the :it-,rompanyiuilprovide, improved menus for eoritrolliint the drawing whieh illustrates two siihserihers` Supervisory signals in sueh systems; andvto telephone lines and the plug-word eouiieetiiig; 70 provide in'r|' ro\'etl means for automatieally i'il'tllll tlllllliitl` tlll \\'ll tlt lltlllfl ltllilitltl.

controlling` the operator`s eii'euit iu eonnet- :ind provided with appa 'attrs'. to t'iirry out t-ion with the plug-oord eonneeting eireuits my present invention. for Such Sygtcm5- lu the drawings the lines A\ :unl ll are Other objects will he apparent Alroin the eaeh proi'iileil willi a suhstiitiou :it whieh 75 following specification. the i'ii'eiiit ot the Iiiu` ii: rinsed when the In tlii"4 invention [supply a riiigfingi relay rereirer is remoi'etl l'rom the wwueli'hooli.` and an operator`s diseonnet'ting relay. hot h in the usual iuriuner` the `'ireuit of the line, associated with a plug` ot the plug-ront eine heilig open when the iereirer is hung; upon meeting eireuit. with eurreut liioin a line eon the sn'iteh--hoohz SO neetion extending' through a third eouduetoi' Liiuh l ot eaeh line extends to terminals of the cord, plug:r and any one olf a pluralit'jr It :l of line springinelts (l (i. iu multiple, of line jaelis, for operating' the said relays and also through a line relay tt() to pole '.l when connection is made with the line. oli :i -entral hattei'y l-`. liimh 2 ot eiieh line Then ll provide a loeliing' relay in the pluf; extends through :i normally,elosetl eoutaet Se wird circuit: and siipply this relay with euittt-432 ol a eutotl' relay t?, to pole lt) nl' rent through the said line eonneet'ion when liattery lt`. Relay tirl is f-onneeted troin pole the subscriber removes his reeeiver `from tlv,l ltl ot liatiery l to terminals` I t ol the jaelts' swittih-hoolc while (,onueetion is iinute with t". in multiple. When relay ttt) is euer-- the line, to cause the latter said relay to gizeil it eloses eontai-t lfl-V (3:3 in the eireuit titl lock the ringing relay in a noteringing poot" a line lamp T. When relay t'il is ener 40 sition until'the connecting,` plugl is removed grim-tl it opens eoutaeis tlr-Y t'i-, and tl-u tt;A` troni the line jiiolt'. The operators dist-,on` and eloses eontiiet Ulm-(3T, eontaet (Sl---v-tt heneetiiie; relay in addition to t'zontrolliug the ing in the eil-enit ol` line lamp T :unt eontaet oliieratoifs eii'eiiit: also helps control a superttl-t'f' heine' iu eireuit with the terminals 95 visory signal. l also provide a supervisory 5 5 ol the jacks C C, whit-h terminals 5 5 relay associated with the said plug oit the are iu multiple.

plugword circuit', For partially controlling ln thipliiig--eord eonneetiug Circuit the the supervisory signal, and a line relay, talking strands tt and li otl iaith plug l) throughbott'i olwliioh relays thesiiliseriheis :init it are eounetted together through eon- 100 line is supplied with current for talking purdenners l. aud lf-l, respeetirely. llaeh plug' poses duringI eonyerlsation. The siil'ieivisory l) and lll luis a ringing relay amoeiateil relay in addition to controlling' the super therewith to eoutrol suitablerout-acts. When either' o the relays 15 l5 is energized, spring visory signa-l also places the loeltiug relay in members lo and .i8 thereof are caused to er.- gage contacts 2O and 2l., respectively, which are connected through conductors 22 and 223,'

respectively, to a ringing generator G, spring member l@ also discngaging contact 11"'.

`Jlach ot the plugs l) and ld is provided 'with a third strand or conductor 24 adapted to furnish a connection through any one ot the' several jack-springs l @t when the plug is connected. with a line jack, to furnish current supply 'for operating the several relays in the plug-cord circuit. i pair of operators disconnect relays and 26 are connested troni the respective strands 2e 24 ot' the plugs D and l, to pole 9 ot battery F, such connections causing these relays to become energized when their respective plugs l are connected with line Jacks. The sccondary o8 69 ot an operators induction coll, an operators receiver 70, and a condenser 7l, bridged from talking strand l1, on

opposite sides of condenser 13, to talking strand. l2, on opposite sides ci condenser 14, preferably as shown, through normallyclosed contacts -3l and 32%33 of each of the relays and 26, in multiple, so that the operators set will be entirely disconnected from the talking strands .l and l2 of the cord circuit when both the relays 25 and 26 are energized.

in impedance coil. T5 is connected from between the magnet coils 01".' the receiver 70, through conductor 39 to pole il of battery F. lhis coil is to enable busy-test to be made hereinafter described, and as claimed in my copending application for Let-ters Patent on busy test for telephone. systems, Serial No. etlll, 5'?, filed herewith,

The arrangement of the operat-ors relays 25 and 26 is practically the same as in my copending application for Letters Patent on telephone. system, Serial No.A 414,078, but in addition to controlling the operators circuit these relays are in this present invention also arranged to control the supervisory signals as will be hereinafter described. llfhen either of the relays 25 or 26 is energized it clos'esa contact Y2-73 in the corresponding supervisory signal circuit.

To each strand 24e of the. plugs l) and l is connected the corresponding ringing re lay l5, through a normally-closed contact Bst-35 ot a locking relay 36,. 'the circuit from each ringing relay l5 extending through conductor 37, rotary. intermittent circuit-closer and conductor 39, to pole 9 of battery F. Each supervisory lamp 4L() is connected through conductor 38 to pole l0 of battery F. I

From talking strand 12, on opposite sides ot .condenser 14,' are connected a pair of supervisory relays, 48 43, to pole l0 of battcry ll. lllhen either of the supervisory -relays d3 e3 is energized it causes spring member. ll2 thereof to disengage Contact -l'l and to engage Contact 4G which leads to the winding of the. corresponding locking relay 36; Vl`hus in addition to controlling the supervisory signals, the relays 43 43 are also arranged to control the circuits of the respective locking relays 36 36. lNhen either 1ol the. locking relays 36 36 is energized it 'causes spring member 34 thereof to disengage contact 35, and spring member 74 .to engage Contact l', spring member 3d beingl connected to the corresponding strand 24. and contact t7 being. connected to pole 9 ot battery l?. l

The operation of the system is as follows: ldlhen a party at substation A desires to make. a call, hc lifts his telephone receiver from the switch-hook in the usual. manner, which closes the circuitJ between limbs l. and 2 of his line and thereby closes a circuit from pole 9 of battery F, through. his line relay 60, line A, and Contact (5l-62, to pole l() of battery F. Current from battery l41 flowing through this circuit energizes line relay 60 and thereby causes same. to close contact 64h65 which bridges the line lamp through contacts Stimm-G2 across battery F. Current from battery l? now flowing through .line lamp 7 lights this lamp which signals the operator at the central station for a connection, whereupon the operator inserts one. of the plugs D or .E into a jack C of line il to answer the call. The plug contacts ll, l2 and 24 now engage jack terminals 3, 5 and 4L, respectively, thereby closing a number of circuits through battery F, which circuits willnow be traced and explained as follows:

llirst. From pole 9 of battery F, through conductor 39, one of the operators disconnect relays 25 or 26 (say 25), strand 2l of the. connected plug, a jack-spring. 4, and cutoff relay 63, to pole l0 of battery F. Current from battery I" flowing through this circuit energizes relay 25.a.nd thereby causes its armature to be attracted and to open contacts 30-3l and 32-83 and close contact 72h73. Although contacts 30V-3l and l2-38 of relay 25 are now open, the operators telephone set is still bridged across the plug-cord talking circuit from talking strand ll, through contacts 30-31 and 32-33 of relay 26, to talking strand l2. ,Contact 72-73 being closed does not cause the supervisory lamp .L associated therewith to light, because -contact 41--42 is simultaneously opened as'will beI hereinbelow described. The current now flowing in circuit 39, 25, 24, 4, 63, also energizes the cut-p' relay 63 and thereby causes its ar1nature to be attracted and to open contacts 61---62 and 6166 and close contact 61w67. Contact olf-JSG being open extinguishes line lamp Z. Contact 61-62 being open discon- .sects pele ,to ont battery F from limb a. .et .1.

lli

(Bti

line A.' Contact til-67 being,r closed connects tirnb 2 of line A to the several linejack terminals 5 5.

Second. From pole 'l0' ot' battery F through supervisory relay 43 on the connected-plug side of the cord-circuit, strand l2, a jack teriniial 5, contact 67H61., line A, and line relaytO, to pole t) ot battery l?. ('iurretit from battery l" tli'nwafng' through this circuit enei'gizes relay et?) and thereby causes its armature to be attracted and to open contact lL-l2 and close contact it-Jill Contact tlf-4t2 now being open prevents the supervisory .lamp 40 associated therewith from displaying a signal. Contact 'tQmtG being closed closes a circuit from pole 9 of I i operator inserts the idle connecting plug ot battery F, through contact 4t2- 445, locking relay 36, strand 24. of the connected plug, a jack terminal It, and cutsotl' relay 63, to pole l0 `if battery Current from battery li Howing; through this latter circuit encrgizes relay 36 and thereby causes its ari'natures to be attracted and to open contact 3ft-35 and close Contact film-4t?, respectively. Contact Bilk-35 now being' open prevents ringing rc- .lay 15 ilroin becomingr energized. Contact Tft-M47 being'closed closes-a' circuit Yt'roni pole 9 ot battery- F, through Contact itTM-74, relay 3U, strand 24, jack terminal Al, and ciit ott relay G3, to pole 1() of battery i?. (lui-- rent from battery F flowing through this latter circuit will .licep relay 3G energized and its armatures attracted, even i't` contact l2-itil is opened, contacts L7-w74- ai'id Llib-Lto being; Vin multiple in the circuit of relay 36. Thus the armatures otl relay 3G are locked in attracted position until the connecting.;r plug is reinoi'or'l :troni the line jack C.

The operator now receives troni the party at sulistatfion A, instructions to connect his line lor cony'erszfition with substation l, whereuiion the operator takes the idle connectiugg plug' uit' th:` pair and tests .line li to ascertain whether it is busy or not, as will now be described.

.ln making' the busy test on line B the operator merely touches the tip contact of the idle connecting plug against a tei'iiiinal 5 oll a jaclt if ol `line l, iii-the usual manner. ll line B is idle thel jack terminals 5 5 will all he disci'innected from the battery li at contact til-(31 which is then opcii, so that the test-ing' plug will bc unable torlosc any complete circuit, by its lip being' touched against one o'l.E the jack terminals 5 5, to gire a signal to the operator` lt' line l is busy, thc jack terminals 5 5 thereof will be connected to pole 10 ollv battery F, through a circuit similar to the circuit including' a sui'ierrisory relay -l and strand '12, established by some other coniii .:tin, ,fir plug' in the systen'i. Under this latter condition `the operator in makingthe busy test closes a circuit lroni a jack terminal 5 of line B, which is connected topole lO of batteryF as .above described,

. pole I() ot battery F.

i li'oni the talking' strands 1l and 12 ol the lplugcord circuit. i `closed closes a circuit lroin pole ll) ol bat- `tcry l", through conductor 23H. supervisory litllt through tip strand 1l ot the testingr plug, contact :l0-3l oil relay 2G, a portion tllot' the secondary ot the operalors induction plugl against thc ring' or sleeve 5 of a jaclt of line ll, an impulse o'l cui'i'cnt lii'oin battery lP flows through the lastsdescribcd circuit i and thereby produces a click 'in the operators receiver 'i0 which indicates to hei' that l line 'l'.l busy, or in use. The loudness of the operators busy click can be regulated by regulating the resistance of the coil 75.

Assuming); that the line ,l is not in use, the

the pair into a liuc, jack C ci line li. thereby closing,r a number ot circuits through battery F which circuits will now bc traced and explained as follows:

First. liroiii pole l) ot' battery li through yconductor 23S), the operaloi"s` disconnect relay Qt'i, strand 2l ot the calling' i'ilug, a )ackspriiig Afl ot line l, and cut-ottI relay (Sil, to Current troni battery F flowing through this circuit cnergizes relay QG and thereby causes its arniatures to be atli'acteiil and to open contacts 2? .-31 and Now the (lontact TQs-Tl bein(ir h lamp 'l-l) which is associated with relay 2h, and contact sociated with the'calling plug, to pole 9 ot battery F. Current l'rom battery F [lowing through this circuit lights the supervisory lamp il0 which shows to the operator that.

signal when thc circuit ol the line is closed` Contact tik-h2 beine' opcn disconnects pole lll ol" battery lf :lroiii limb 9 nl line ll. (1ontact (3L-'(37 beinfr closed connects limb Qrof liuc B to the several line-jack terminals 5 li.

Second. From pole 9 ct' battery F through conductor 3S). intermittent circuit-closer H, coiiductoi' 37, ringing relay lvassociated with the calling plug, contact 2l5-3t of liicliing relay ISG, strand 2l ot the calling plug, a jack-spring' `l ot linc ll, and `cut-oit' relay tl, to pole lll olt battery li. ii'rcnt t'i'oiii battery l flowing through this circuit, when the ciicuit-closer ll closes the circuit, encrg'ixes ringing relay l5 and thereby causes its ariiia'tiires to be attracted and to gizes relay 36 and thereby close contacts 16M-2O and 18-21, Arespectively, armature 1G also opening contact lli-1T. lflvlhile the ringingrelay 15 is energized, a circuit is closed 'troni ringing,` generator Ct, through conductor 22, contact 20-l6 of ringing relay l5 which is associated with the calling plug, strand 1l, jackspring 3, liinb l of line E, the ringer and condenser at sul'astation liinb 2 ot line B, contact (3l-6T of relay (i3, ac r-terniinal 5, strand 12 oi the calling plug, contact 18---01 of ringing relay l5, and conductor 23, back to the generator G. Current lloiving from the generator G through this circuit rings the ringer-at sul'istation B and thereby signals theparty at this telephone. The ringer substation B rung intermittently, due to the tact that the rii'igingv generator circuit over line B is closed intermittently by ringing relay l5 which energized interinittently troni battery liTl through the intermittent circuitcloser l lt will be seen that the ringing` relay l5 connects the source oipv .ringing current G di rect 'to `the cor(l trends and line, Without causing the rii ne; crirent to traverse any coils or other i stan or iinpedances at 'the central statin i which would hinder its new somewhat. ie will also be seen that the 'f 'lo primarily controls the ap,L plication et nginglzj current io the line, and that the intcrrupter il primarily controls f Y circuit ot the ringing; relay l5, when connection inad .i with a. line.

who the p r j" substation B answers and li receiver troin the itis his e cir, he Ycloses the circuit between limbs l and 2 oi' 1ois line and thereby closes a circuit troni polo 'll ot battery F, through supervisory relay '-i which is associated with the calling` plus', strand 1Q, liacketcrniinal 5 oit line E, Contact 'lA-6l ot' relay 63, line ll, and line relay 60, po 9 ot battery F. Current troni battery liV1 "locving through this circuit energizcs relay lo and thereby causes its armature to be attracted and to open contact lll and close contact ft2 46. Contact fll-1l2 being` open extinguishes lamp t0 which indicates to the operator that the party at substation l?) has answered his call. Contact sQ-l being` closed closes a circuit troni pole 9 ot battery li, through contact 42e-46, locking' relay 3G, strand 24; ot the calling' plug', ack-spring l, and relffyY 63, to pole 10 ot battery F.. Current 'troni battery ll" tiowing through this circuit enercauses its arniatures to be attracted and to open contact M -35 and close contact-Tesa@respectively. Contact 3er-35 beings,` open renders ringing relay 15 incapable ott further operation and thereby stops theA ringing over line B. Contact Tle7 being closed closes a circuit troni pole 9 ot battery l?, through Contact @iL-Te, locking' relay 36, strand Q4.- o't the calling i v insoso plug, jackspring 4 of line B, and relay 63, to pole lO of battery F. Current troni batu tery F flowing through this latter circuit- Will keep relay 36 energized and its arinatures attracted, even it Contact 42e-46 is opened, contacts 47-74 and 4t2-1lb being` in multiple in the circuit of relay 3G. Thus the armatures of relay 3G are locked in attracted position until the connecting` plug associated therewith is removed from the line jack C. Now the parties at substations A and B are connected for conversation with each other, over limbs l and 2 of their lines and talking strandsv l1 and 12 of the plug-cord circuit. `When the conversationI is coinpleted, the party at substation A hangs his receiver upon the switclrhook, which breaks the circuit of his line in a manner Well un-4 derstood and thereby stops the flow ot current through the supervisory relay 43 which is associated with line A. This supervisory relay t3 is now denergized whereupon the armature thereof releases and closes the back contact/l2 4l which closes a circuit troni pole 9 ot battery F, through contact 4t2-4l, Contact. YSMTEL supervisory lainp l0 which is associated with line A, and conductor 3S, to pole l0 of battery F. Current 'flowing troni battery F through this latter circuit causes the supervisory lainp 40 to light and thereby convey to the operator the signal tor disconnection of line A.

The party at subst-ation B by hanging his receiver upon the switch-hook, controls circuits and gives his disconnect signal to the operator the saine just described in connection with line A. New the operator, having received both disconnect signals .ons A and B, withdraws the troni substati connection plugs l) and E from the line jacks and therebyT opens the circuits of the locking` relays 3G 36 and the operators disconnect relays 25 2G, over the line connections, thus denergizing' all of the relays 36, 3C, 25 and 26 and causing the armatures thereoit to release. Relays 36 36 now close contacts 34 35 in the respective circuits of ringing;` relays'l 15, but these lat ter relays larenot energized by suoli contacts being" closed because the circuits 0f the relays l5 l5 over the line connect-ions are now open at the connecting plugs. Relays 25 and 26 now open the contact-s 72-78 FL-73 in the respective supervisory lamp circuits and thereby extinguish the said lamps LO 40. Now all ont the circuits and apparatus are restored to normal position and condition preparatory tor another cycle of operations as just described. lty Will be seen that the locking relays 36 keep the ringing relays l5 l5 from ringing back on the lines after the parties at the substations A and i3 have hung; their receiyers upon the switch'hooks and th aervisory relays t3 have been ,d Y. opened conu tziets Lt-tt'i ft2-ith in the first close/il piithsi through the loeliing rehiyg Si?, :3th while eoni'ieetion is itl ninile with the lines, iliie to eontiietsv itiimflll- #i1-Tlf bi1-,ing i'loiieil.

iiittention is enlleii to iny two eo-peinling :ipplieiit'ionn tieriiil NoftitlthtS-t, tileil No- '.eintier i?, i910, :intl Seriiil No. trilt-,042, tiled tngnnt lil1 fttllft.

lY lo not wish to liinit this invention to nll ot the inirt'ieiihir details ot eonstrnet-ion, or Vto the piii'tienliii' typen ot iiiiiiiiriitnn, herein ;-=h,o\i'n, :is iniiny inotlitieiit'ionb iniiy he iinitle therein without thriizirtiing troni the neoiio ot the iipi'ieniletl eliiiins.

l. A. telephone line extending to ii eonneetion terniiinii :it ibi eentiriil `ntiitioni :i reliiy :Vix fwteil with the" line for controllingl ai eigz'izil, i snitiihle signnl to he eontrolleth ai ronneet'ii'ig' eircnit' it'or the lineR i source o ringing current iissoeiiiteil with the eonieeting eirenih ii ringing relziy iissoeiiitetl with the eoniieeting` eirfiiity 'tor eonneeting the with :i portion ol the eonneeting eireiiit :intl the line when eonneetioii is iniirle with the line7 n siiiiei'i'ieoifr relieV nneioeiiiteil with the i-onnetftii'ig eireiiit :intl inhiiiteil to he oner- :itetl hy eiirrent over the line when eonneetion in nitide with the line iiiiil the hitter is in one, ii inciting reliiy iiniler control ot the eiigieri'inory rehiy, zi, eontiiift in eii'eliii', with the ringing relny nini i'oiitrollei'l hy the lorhing reliij'u :init iiieiinn `tor supplying the iniging rehiy with enrrent ore' :i line ronnertion tlirongh the tiret ii'ientioneit reliiy :intl the wiiitl eontiiet ot' the loeliiiig rehiy, tor enerziting the ringing rehiy, when eonnee-A tiin is ninile with the line, the ringing rehiy tieing i'eiiilereil iiieiiinihle off operiition hy the toelting rehiy when the hitter in enerA gimeil, hy the operation o ti the eiiiieri'isonv i'e-4 liiy ii'hieh in tnrn energixeil hy ein'rent over the line when ronneetion is ninth.: with the tin?y :intl the hitter in in nwe.

i2. it telephone line extending to :i phi nlitix otf eonneetion terminan nt, :i eentriii stir tion :i rehiy nssoeiiitetl with the line 't'oif eoiotzjnllitin,f :i ssigei'niil, :i snittilile s-iiginil yto he eiintiolleii, :i eonneeting eiienit YAtor the line, ii :ionree olf ringing entrent iisnoeiiiteit with the eonneetiiig eirenit, :i ningiiie;l relaiy ne Qoeiiiteil with the ei'inneeting eii'enit toi' eon- Anetting the :niiet sonree oit ringing enrrent in eirenit with ii portion of the eonneetling rireiiit' enit the line when connection is n'nnle i'. ith the line. :i eiii'ieri'iSiory rehiy iissoeintetl with the eonneeting eircliit :intl :iihiiited to he onei'aitei'l hy eiirrent over the line, when eonneetioii, iii iniitle with the line nini the hitter is in line, n hit-hing reliiy innler eon trol o't' the supervisory relay, :i eontiiet in eii'enit with the ringing reliiy :intl irontrnllel'liy the looking reliiy, :iiiil niezinss For ,iinoiilying the ringing.; rehiy with current niiiil A onree, et' ringing entrent in eii'eiiit over ii line connection through thtl tirst nientioneil i-elziy :intl the `siiiil eontziet of the looking rehiy, for operating the ringing reliiy. when eoiiiieetion is niziile with tiny one ot the Sziiil line eonneetion terniiniils, the ringing reliiy heilig i'einlerei'l ineiipirhle of operation hy the loelting i'ehiy when the hitter is energized hy the oneriitionoi:I the Sie herrin-ori i-eliiy wliirh in tiirn energized hy enrrent over the line when connection is niiiile with the line unil the hitter iS in use.

El, )i telephone line extending to :i oonneetion terniiinil :it :i eentriil .strition` :i rehiy iiisnoeiiiteil with the line 't'oif Controlling :i signal, :i niiitiihle :signal to he eontrolleil. :i eonneeting eirenit l'oi' th'e line, :i sonree ot! ringing entrent :isnoeiiiteil with the eonneeting eirixiiitj :i ringing reliiy iissoeiiiteil with the connecting eii'eiiit; for eoiiiieetiing,l the siiiil source ot ringing eiirrent in eireiiit with :i portion ot. the sind connecting eiroiiit :init the line when eonneetion is nitide with the tine, :i soiirt'e ot ilireet eiiri'ent zint-l iin intermittent eireiiit-eloser in eireiiitJ with the ringingl rehiy, ii supervisory reliiy asnoeiziteil with the eonneetingeirenit :intl :nhipteil to he oneriiteil hy ein'rent over the line when eonneetioii, is niiiite with the lini :intl the hitter is in ilse, :i loeling reliiy nniler eontii'ol otf the `niipeiw'isiii'y rehiy, ii eontiiet in eireiiit with tlieringing i'ehiyziiiil eontrolled hy the loeliing reliiy, :intl niezinny tor supplying the ringing rel'iiy with riirrent over ii line ei iiiieetiiin ihrongli the first n'ientioneil rehiy :init the ieiiil eontiiet ol" the loelting rehiy, tor operiiting the ringing reliiy7 when eonneetion in nnnte with the line, the iiziitlinten niittent eii'enit,-eloser onei'nting the riliging rehiy interinittently, the ringing reliiy heilig reiiilei'eil iiieiiiiiihle ot" oneriition hy the loelcing rehiy when the hitter in energized hy the one 'iition ol the supervisory reliiy whieh is lin tnrn energized hy eiirrenti over the line when eonneetion in iniitle with the line :intl the hitter in in iine.

Ll. it telephoneline exteniling to ii plie rnlit'y of oonneetion terniiiinln :it :i eentrzil ntzition, :i relirv nnsoeinteil with the line lolf eoiitrolling ii nigniil. ii .siiiiiihle lwignril to lie eontrolleih :i eoiinei'ting t'ii'eiiit loi' the line, :i Aoiiiee oiI ringing oni'reni :iswoiiiiteil with the eonnreting eiri'iiit, ii ringing relziy :insoeiziteil with the eonneeting eireiiit t'or eon neetiiig the .n.iiil .sonree ot ringing eiirrent in eii'enit with :i portion otj the eeiiiieetiing eirenit' iinil the line when eonneetion is nitide with the line, n \'oi|ree olE ilireet eiirrent nii'tl :in intermittent eii'enit-eloser in eirenit with the ringing reliiy, :i ASupervisory ieliiy :insoeiiiteil with the eoniieetiiigl eiroiiit :intl :nhiiiteil to he oiiernteil hy enrrent over the line when eonneetion is nniile with the line :intl the hitter is iii iise, :i looking reliiy iinilei' eontrol ot the supervisory rehiy` :i contziet in eiri-iiit with the ringing reliiy :intl

vlO

controlled by the locking relay, sind ineens for supplying the ringing relay with current over e line connection through the tiret mentioned relay and the seid Contact of the locking relay, for operating the ringing relay, when connection is inode with any one of the Seid line connection terminale, the sind intern'iittent circuit-closer operating the ringing,- relay intermittently, the ringing relay being rendered incapable of operation by the lockingr relay when the latter is energized hy the operation ot' the Supervisory relay whichlis; in turn energized hy current over the line when connection is ino de with tne line and the letter is in use.

A metallic telephone line extending to n connection terminal at :1 central station, a relay associated with the line :tor controlling u signal, ii suitable signal to be controlled, e connecting circuit for the line, seid connecting; circuit having c metallic talking circuit extending therethrough and adapted to he connected. in circuit with the metallic line, a, source of ringing current associated rwith the connecting circuit, c ringing relay associated With the connecting circuit for connectingl the seid source of ringing current in circuit with a portion of the said metallic talking circuit and the metalli c line when connection is merle with the line, c Supervisory relay connected to :t strand ot the seid metallic talking circuit and adapted to be operated by current over the line when connection'is made with the line and the letter is in use, oJ locking relay under control the supervisory relay, a Contact in` ycircuit With the ringing relay and controlled. hy the locking relay, e third strand in the connectF ing circuit connected in circuit with the Seial contact ot the locking relay and the ringing relay, cnil e third contnctmember negocietefl with the line connection terminal whereby the ringing relay is supplied with current through the tiret mentioned relay, the Said third strand of the connecting circnit und the scid contact ot the lockingr rcley, to opeinte the tiret mentioned relay and the rinizgingl relay, When connection is inside "with the line, the ringingn relay being; rcu dered incapable ot operation hy the locking` .relay when the latter is energized hy the operation oit the Supervisory relay which in in turn operated by current overlhe line when connection is mode with the line und the letter is in use.

(l. A metallic telephone line extending to e plurality oi connection terminals at o central Station, :i relay associated with the line for controlling a, signal., o, suitable signel to be controlled, n connecting circuit for the line, said connecting circuit having :L metallic talking circuit extending; therethrough und adapted to be connected in circuit with the metallic lino, a source oli ringing current associa-ted with the connectingq Loeeeeo nected to o strand of the seid metallic tellt-V ing circuit and. adapted to be operated by current orer the line when. connection is merle with the lineencl the letter is in use, c locking relay under control of the super-- Visory relay, rt contact in. circuit with the ringing relay and controlled oy the lockingI relay, o 'third strand in the connecting cir cuit connected in circuit. with the said. contact ot the locking relay and the ringing; relay, enti e third contact-member associated with each oi the Seid line connection terminals wlierehy the ringing relay is supplied With current through the first mentioned relay, the scid third etrand ot' the connecting circuit and the Contact of the locking reluy, to operate the first mentioned relay and the ringing,n relay, When connection is mede with rany one oit the scid line connection ter niinzils, the ringing. relay being rendered incapable of operation hy the locking relay when the letter is energized hy the operation of the supervisory relay Which is in turn ooe-rated by current over the line when connection is merle with the line and the letter is in use.

7. A metallic telephone line extending to n connection terminal :tt 1 central station, e relay associated with the line for controlling n signal, ay suitable Signal to he controlled, connecting circuit for the line, Seid con necting; c' cuit haring :L metallic talking circuit @intending therethrough und adapted to he connected in circuit with the metallic line, ev si; rce oit rircingcurrent nseocizitetl with the owner/tingl circuit, a ringing relay associated Ywith the connecting' circuitfor connecting the seid source of ringing current in circuit with c port-ion ot the Seid metallic talking circuit and 'the line when connection :nude with the line, :i Source of tliect.,A current und un intermittentcircuitcloser connected in circuit with the ringing relay, o supervisory relay connected to e strand of the Seid metallic talking circuit :incl adopted to oe operated by current over the line when connection is mede with the line und. the lutter is; in une, locking relay under control ot 'the supervisory relay, c Contact in circuit with the ringing relay :incl controlled hy the locking relay, o third strand in the connectingx circuit connected in circuit with the Said Contact of the locking relay, thc ringing relay, the intermittent circuit-closer, and the scid source of direct current, and n third contoct-nic1nher aesoci ated with the line connection terminal whereby the ringing relay is Supplied with current through the scid content of the lll) lll

locking relay, the saicl third strand oit the connecting circuit, and a line connection in clutling the tirst. mentioned relay, for operating the ringing relay, when coiniection is made with the line.` the interiuitteiit circuitu closer operating the ringing relay interinittenlly, the ringing relay being rendered in- :apable of operation by the olieration ot the locking relay when the latter is energized by the ope 'ation ot' thc sipervisory relay which in turn operated by current over the line when connection is made willi the line and the hitter is in use.

ti. A metallic telephone line extending to a plu ality o'l` connection terminals at a central station, a relay associateil willi thc line for coiitrolling a signal, a suitable signal to be controlled, a connecting circuit tor the line, Said connecting circuit haring a metallic talking circuit extending therethrough and adapted to be connected in circuit with the metallic line, a source ot' ring ing current associated with the connectingl circuit, a ringing relay associated willi the connecting circuit tor connecting the said source of ringing current in circuit with a portion otl the said metallic talking circuit an the line when connection is made with the line, a source 0l direct current and anl intermittent circuit-closer connected in cirenit with the ringing relay, a supervisory relay connected to a strand ot the said mctallic talking circuit and adapted to be operated by current over the line when connection is niatlc with the line and the latter is in use, a locking relay under control ot` the supervisory relay, a contact; in circuit with the ringing relay and controlled by thc locking relay, a third stra nfl in the connecliing circuitconnected in circuit willi the said Contact ot the locking relay, the ringing relay, the intermittent circuitcloser, and thc said source ot' direct i'zurrent, and a third contact-nien'ibeiuassociateifl willi each ol` the said line connection terminalsl whereby the ringing relay is supplied with current through the said Contact ol the locking re lay, the said third strand ott the connor-,ling circuit, and a line connection including` the firstinentioiied relay, for operating thc ringing relay, when connection is made with any one ot the said lineI connection terminals, the interniitlent circuit-*closer operating the ringing relay interinittently, the ringing relay being rendered iiiicapable oli' operation hy the operation ol" the locking relay when the latter is energized by the ope-ation ot the supervisory relay which is in turn operated by current over the line when connection is niailc with the line and the latter is in use.

l). il metallic telephone line extending lo a plu ality ot connection terminals at a ccnl lral station` a relayassociated with thc line l'or controlling a signal, a suitable signal lo be controlled, a metallic connecting circuit lor the line, a source ot' ringing current associated with the connecting circuit, a ringing relay lor connecting the Source ot' ringing current in circuit with thc,inetallic connecting circuit when connection is made with the line, a third conductor in the connecting circuit and a third contact-nieinber in each ol the said line coinieciioii terminals cooperating to supply lhe ringing relay with current over a linc connection through the lirslv mentioned relay when connection is made with any one ol' the said line connection terminals, an iiitcriniltent circuit-closer in circuit with the ringing relay Al'or operat-` ing the latter intermittently, a supervisory relay connected with the metallic connecting circuit to be operated by current over the metallic line, a locking relay controlling,r the circuit ol the ringing relay, a Supervisory signal under control ol the supervisory relay, means whereby the locking relay' is initially maler control o'lE the supervisory relay so that the latter when operated energizes the'locliiiig relay with current over the said third line connection, for operating the locking relay, lhc latter being provided with means For closing its own circuit through the said third line connection, when ope ated, whereby it loi-lts ilselt in operated position until the connecting circuit is disconnected l'roni the line. i

ltl` lin a telephone system having lines, a connecting circuit loi the lines, a source o'l' ringing current associated with the connecti'ng` circuit, a ringing relay associated with the connecting circuit and operated ove' a circuit including a line connection t'or connecting the saidv source ol' ringing current with the line when connection is made there willi, a locking relay controlling the circuit ol` the said ringing relay, a supervisory Signal, an operalni"s circuit, a pair of relays controlling the circuit of the, supervisory signat` means` whereby one ol the relays of the pair coiilrols the circuit ol the said lockingl relay, and means whereby the other said relay ol the pair controls` the opcators circuit.

ll.. ln a telephone system having a plurality ol lines` :i relay associated willi each oli the linesl tor controlling respective signals, suitable signals to lic controlled, a connect ing circuit toi' the lines, said connecting eirciiit terminating in a pair olE coniiecting plugs adapted to be connected with the lines, :in ope ator`s telephone set normally connected with the connecting circuit, an opei'alor`s disconnect relay 't'or'each connecting plug through which the opci'alofsl telephone set is coiiniartial` in multiple, with the con-` iicctiiig circiiil` and mi ans whereby the said opcralofs disconnect relays arc supplied willi ciiri'ciil over respective `lintI connections through respective relays which are associated willi the lines, l'oil operating all of the said relays, When connection is made between the corresponding connecting plugs and 'the lines, whereby the operators telephone set is entirely disconnected from the connecting" circuit when both of the said operatorls disconnect relays are operated.

l2. ln a 'telephone system having a plurality of lines each terminating in a number of mannection terminals in multiple, a relay associated with each oi the lines for controlling reer iective signals, suitable signals to be controlled, a connecting circuit for the lines, said connecting circuit terminatingin a pair ot connecting plugs adapted to be connected with the lines, an operators telephone set normally connected with the connecting circuit, an operatoris disconnect relay for each of the connecting plugs through Which the operators telephone set is connected, in multriple, with the connecting circuit, and means whereby the said operators disconnect relays are supplied With. current over respective line connections through respective relays which are associated With the lines, when connection is made bet-Ween the corresponding connecting plugs and any of the said line connection terminals of the respective lines, for

operating' all ot the said relays, whereby the operatorls telephone set is entirely disconnected :from the connecting circuit when both of the said operators disconnect relays are operated 13. ln a telephone system having a plurality ot metallic lines, a relay associated with each of the lines for controlling respective signals, `suitable signals to be controlled, a connecting circuit for the lines, said connecting circuit having a metallic talking circuit extending 'therethrough and terminating in a pair oit connecting plugs adapted to be connected with' the lines, an operators telephone set normally bridged across the metallic tall;- ing circuit ot the connecting circuit, a pair of operators disconnect relays associated with the respective connecting plugs and through which the operators telephone set is bri dgcd, in multiple, across the metallic talkino, circuit ot the connecting circuit, a third conductor 'in each connecting plug, and a third contact-member for each line coperating with the said third conductors ot the connecting plugs, the said operators relays lacing connected in circuit with the respective third conductors ot the connecting` plugs whereby the latter said relays are supplied with current over the respective said thirdconductor connections between the corresponding connectingl plugs and the lines, through .respective relays Which are associated with the lines, when connection is made with the lines, 'tor operating all of the said relays, whereby the operators telephone set is entirely disconnected from both strands of the metallic talking circuit olz the connecting roeoeo circuit Wh en both or the connecting plugs are connected with respective lines.

lll. ln a. telephone ysystem having a plurality of lines each terminating in a number of connection terminals in multiple, a. relay associated with cach of the lines for controlling respective signals, suitable signals to be controlled, a connecting` circuit tor the lines, said connecting,r circuit having a metallic talking` circuit extending therethrough and terminatingl in a pair oit connectingl plugs adapted to he connected with the linee, sii operators telephone setl normally bridged across the metallic talking circuit ot' the con-- necting circuit, a pair otoperators disconnec-t relays associated with the respective connecting plugs and through which the opcrators telephoto set is bridged, in multiple, across the metallic talking circuit of the connecting` circuit, a third conductor in each connecting plug, and a third contact-ineinber 'in each otv the said connection terminals of the respective lines cooperating with the said third conductors or.' the connecting plugs, the said operators relays being` connected in circuit Withthe respective 'third conductors of the connecting plugs whereby the latter said relays are supplied With current over the respective said third-conductor connections between the corresponding connect/nig plugs and the lines, through respective relays which are associated with the lines, when connection is made With any of the said connection terminals of the respective lines, for operating all oit the said relays, whereby the operators telephone set is entirely disconnected .trein beth. strands of tlieinetallic talking,1 circuit of the connecting circuit when both of the connecting plue's connected with respective lines.

l5. ifi metallic telephone line extending;

from a substation to a source of electriity at ceiiaral station, a line signal, a line ren lay included in the s id line :tor operating; the line signal, a plurality or' connection ter minals :for the li e, havingn tact-members con ected in multiple to limb olf tl' ,i metallic line, aiid'respective sleeve contact members connected together and normally disconnected troni the other limb ol the metallic line, and a cut-oil relay connected with a third contact member of each ot' the said connection terminals and adapted to renc the line inoperative without denergizing the line relay, and to disconnect a limb et the metallic line from the said source and connect the said limb with the said sleeve Contact members of the said connection terminals, when connection is made with the lineu i6. vln a telephone system having` lines, a

signal for cachotj the connecting plugs, an

respective conopcrators circuit, a pair of relays for each of the supervisory signals for controlling the operation thereo and means whereby a relay of each pair controls respective multiple connections of the operators circuit with the connecting circuit, the last mentioned relays being always operated at the time their respective connecting plugs are connected with nnes.

17. The combination with a metallic telephone' line having a plurality of connection terminals and a relay associated therewith, et' a. connecting circuit for the line, a source of ringing current associated with the connecting circuit, a ringing relay associated with the connecting circuit whereby the source of ringing current is connected direct with both limbs ol' the line when connection is made therewith, an interrupter for primarily controlling the circuit of the ringing relay through the first mentioned rela when connection 1s made with any one of t e said line connection terminals, vhereby the rinoing relay is operated intermittently, a loc ing relay for controlling the circuit of the ringing relay, and means for operating the locking relay when connection is made with the line and the latter is taken tar use.

i8. The combination with telephone lines and relays associated therewith, of a conu necting circuit for the lines, a sourcr-l of ringing current, a ringing relay in circuit with a line relay when connection is made with a line and adapted and arranged to primarily connect the source of ringing current direct with a portion of the connecting circuit and the line whereby all other apparatus is eliminated from the ringing circuit, a locking relay :tor controlling the circuit of the ringing relay, and `means for operating the locking relay when connection is made with a line and the latter is taken for use.

l5). The combination with a telephone line having a relay associated therewith, of a connecting circuit therefor, a source of ringing current associated with the connecting circuit, a ringing relay for applying the ringing current to the line when connection is made therewith, means for rendering the ringing relay inactive when connection is made with the line and the latter is taken for use, the ringing relay being operated through the line relay and being arranged to apply the ringing current direct to the line whereby all marginal line resistances employed for operating such systems are done away with. i

As inventor of the foregoing I hereunto subscribe my name in the presence of two subscribing witnesses this 17th day of February, 1908.

ELMER oonwIN.

lVitncsses FREDERICK R. PARKER,

liRANK J. RYAN. 

